Lubricant containing alkyl piperidine salts



Patented Dec. 24, 1946 UNITED STATES PATENT OFFICE LUBRICANT CONTAININGALKYL PIPERIDINE SALTS George E. Barker, Pittsburgh, Pa., assignor toElgin National Watch Company, Elgin, 111., a corporation of Illinois NoDrawing. Application August 3, 1944,

Serial No. 547,979

8 Claims. (01. 252--34.7)

It is known that when relatively moving surfaces are supplied with aninterposed lubricant, the coefficient of friction is normally reduced toa value which i essentially determined by the characteristics of thelubricating agent, the

desired chemical and physical attributes, by add.-

ing as an oiliness agent a small proportion of a N-alkyl piperidine saltof a fatty acid. Such mixtures are as non-corrosive as the basiclubricating agent and are stable and homogeneous under all normaloperative conditions for the selected basic lubricating agent, which forsome of the materials can cover the range of temperatures between minus60 degrees and plus 150 degrees F. The additive also has the effect ofimproving the rust inhibition, thereby reducing or eliminatingthequantity of inhibitor which preferably is added e. g. to ester typeor ester containing lubricants.

The basic lubricating agent employed in accordance with this inventionis a fluid organic composition containing aliphatic groups. Thisincludes the lubricating oils of mineral origin, commonly known asparamn and naphthene base oils, together with lubricating oils ofanimal, vegetable and marine origin such as neats foot, porpoise, sperm,castor, etc., oils, and the lubricant set out in my copendingapplication Ser. No. 372,136, now United States Patent No.

The oiliness agents are in general waxy solids or viscous liquids, bythemselves, which are essentially insoluble in water but soluble in thefat solvents and in organic lubricants. They may be prepared bythoroughlymixing, in liquid form, equivalent amounts of the fatty acidand the alkyl piperidine.

EXAIWPLE I A mixture of 6.2 grams (0.02 mole) of cetylpiperidine and 5.7grams ..(0.02 mole) of stearic acid was warmed in an oven (80 degreesC.) until the stearic acid was completely melted and dissolved in thecetyl piperidine. The liquid was thoroughly stirred to insurehomogeneity and reaction, and allowed to cool to a nearly colorlesswax-like solid.

EXAMPLE II An 88.6 gram (0.312 mole) batch of stearic acid was melted inan oven degrees 0.). To the melted solid was added 79 grams (0.312 mole)of dodecyl-piperidine, with vigorous stirring. The product on coolingremained a liquid for about 48 hours before crystallizing to a slightlyyellow waxy solid.

EXAMPLE III A mixture of 5.96 grams (0.02 mole) of ricinoleic acid and5.06 grams (0.02 mole) of dodecylpiperidine was thoroughly agitated andallowed to stand for twenty-four hours. The product was a yellow viscousoil.

The fatty acid should have at least 5 carbon atoms (e. g. valeric acid)to avoid possible water solubility or attack which may occur with thesalts of acids containing 4 or less carbon atoms,

and the upper limit of carbon content is around 30'atoms as the highermembers give compounds which have poor solubility in petroleumlubricants at low temperatures. Saturated straightchain aliphatic acids,together with branch chain acids having methyl, ethyl, etc., groups inthe branch or branches, such as Z-ethyl-hexoic acid, unsaturated acidssuch as erucic, oleic, undecylenic, etc., and hydroxyl-substituted acidssuch as ricinoleic, can be used, within the prescription of having5 to30 carbon atoms.

The alkyl substituting group in the piperidine complex likewisepreferably has 5 to 30 carbon atoms, although as low as a methyl grouphas been found to exhibit the effect of increasing the oiliness thoughnot to the extent of the preferred groups. The group should have atleast 5 carbon atoms, connected to the nitrogen atom of the piperidinering. The term piperidine also includes herein compounds in whichhydrogen attached to carbon atoms of the ring has been replaced by alkylgroups such as methyl, etc. 2-ethyl-butyl, 2-ethylhexyl and highermembered chains and branches, that is, branched chain groups, can beemployed.

In general, it is preferred to have from 11 to 26 carbon atoms in theacid chain, and 11 to 16 carbon atoms in the alkyl chain.

Such oiliness agents are customarily employed in proportions of 0.05 to1.0 percent by weight of the lubricant. In general, after a particularquantity has been added, the increase of effect diminishes as more isadded. Mixtures of alkyl piperidine salts, each of the type abovedescribed,

3 may be employed. In preferred preparations, the salts are present asgroups of isomers, whereby low melting points are assumed.

Comparative effects of the presence of the oiliness agent and specificexamples of composition are indicated in the following table:

TABLE Coeflicients f friction 0 f steel on sapphire, lubricated Cool. 01Lubricant met Pennsylvania oil, Alchlor treated 21.7 c. s. at 100 0.112Same oil+0.2 per cent dodecylpipcridine stearatc 0. 094 Same oil+0.2 percent dodccylpiperidine lauratc 0.101 Same oil-+0.2 per centdodecylpiperidine crucate; 0. 090 Same oil+0.2 per centdodecylpipcridine cerotate ll. 093 Same oil+0.2 per centdodecylpipcridine rieinoleate 0. 099 B-amylthioetnyl B-benzylthioethylether 0.124 B-amylthioethyl B-benzylthioctliyl ether+ centdodecylpiperidinc stcm'atc 0. 0077 Benzyl phenylundecouoate 0. 109Bcnzyl phenylunneconoate+02 per cent dodi-cylpipcridinc stenrate 097Phenoxyphenyl octane 107 0 Phenoxyphenyl octane-+0.5 per cent dodccstearatc 0. n-Amyl phenylundecanoatc 0. n-Amyl phenylundccanoate+0.5 percent dodecylpipcridine ricinoleate 0 40 parts diethylene glycoldicaproate 0 0.1 part tcrt-butyl catechol 40 parts diethylene glycoldicaproate 60 parts benzyl phenylundccanoate 0.1 part tert-butylcatechol 0.5 part cetylpiperioine stearatc From this it will be notedthat the coefiicient of these lubricants, already low, can be reducedpercent or more by the action of the oiliness agent.

The alkyl piperidines may be prepared in various ways. For example, suchpreparations may proceed:

A. Dodecylpiperidina-4 grams (0.52 mole) of piperidine were mixed with45 cc. of water in a 500 cc. round bottomed flask fitted with-anefficient reflux condenser and a dropping funnel. 140 grams (0.56 mole)of normal dodecyl bromide (prepared in accordance with OrganicSynthesis, Collective Volume I, page 29 (1941), John Wiley & SonsCompany, New York) were added to the solution in the flask, and theresulting two-phase mixture was heated to refluxing. Then, while thecontents of the flask were kept at reflux, there was slowly addedthrough the dropping funnel a solution of potassium hydroxide in 51 cc.of water. Refiuxing was continued for three hours after completion ofthe addition of the potassium hydroxide solution. When the mixture hadcooled, the aqueous layer was separated and discarded, and the oil wasdistilled over solid potassium hydroxide (10g). The material boilingbetween 135 degrees C. and 160 degrees C. at a pressure of approximately1 mm. of mercury was collected and was redistilled. During theredistillation, the fraction boiling between 120 degrees C. 140 degreesC. under a pressure of about 1 mm. of mercury was collected as product.The higher boiling point in the initial distillation was presumablycaused by superheating due to distilling the dodecylpiperidine out ofthe fused potassium hydroxide in the still. The yield ofdodecylpiperidine was 79 percent of the theoretical (104 g.).

B. CetyZpiperzdina-The procedure is exactly as above fordodecylpiperidine, except that cetyl chloride, in correspondingmolecular proportion, was substituted for the dodecyl bromide. Theproduct, cetylpiperidine, distilled between degrees C. and degrees C.under a pressure of approximatel 1 mm. of mercury. It showed a meltingpoint of 19-20 degrees C.

It will be understood that the invention is not limited to theillustrated practices, but may be practiced in many ways within thescope of the appended claims.

Iclaim:

1. A lubricant consisting of an organic lubricant liquid havingdissolved therein from 0.05 to 1.0 percent of an alkyl-piperidine saltof a fatty acid, the alkyl group having from 5 to 30 carbon atoms andthe acid group having from 5 to 30 carbon atoms.

2. A lubricant consisting of a hydrocarbon oil lubricant havingdissolved therein from 0.05 to 1.0 percent of dodecylpiperidinestearate.

3. A lubricant comprising in major part an ester of an aryl-substitutedcarbon-chain acid having dissolved therein from 0.05 to 1.0 percent ofan alkyl-piperidine salt of a fatty acid, said acid group having from 5to 30 carbon atoms, the said alkyl group having from 12 to 16 chaincarbon atoms.

4. A lubricant consisting essentially of an organic lubricant liquidhaving dissolved therein from 0.05 .to 1.0 percent of analkyl-piperidine salt of ricinoleic acid, the said alkyl group havingfrom 12 to 16 chain carbon atoms.

5. A lubricant consisting essentially of an organic lubricant liquidhaving dissolved therein from 0.05 .to 1.0 percent of analkyl-piperidine stearate.

6. A lubricant consisting of an organic lubricant liquid consisting atleast in major part of an aralkyl compound having at least five carbonatoms in an aliphatic chain, together with about 0.5 part of analkyl-piperidine salt in which the piperidine alkyl group contains fiveto thirty carbon atoms in chain connected to the nitrogen atom of thepiperidine ring and in which the acid group of the salt is an aliphaticacid having five to thirty carbon atoms.

7. A lubricant consisting of an organic lubricant liquid consisting atleast in major part of an aralkyl compound having at least five carbonatoms in an aliphatic chain, together with about 0.5 part of analkyl-piperidine salt in which the piperidine alkyl group contains from11 to 16 carbon atoms in chain connected to the nitrogen

